This patch enhances the existing bit operation when f2fs allocates SSR blocks.
Signed-off-by: Jaegeuk Kim <[email protected]> --- fs/f2fs/segment.c | 50 ++++++++++++++++++++------------------------------ 1 file changed, 20 insertions(+), 30 deletions(-) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 74c4748..5fa519f 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -132,47 +132,37 @@ static unsigned long __find_rev_next_zero_bit(const unsigned long *addr, unsigned long size, unsigned long offset) { const unsigned long *p = addr + BIT_WORD(offset); - unsigned long result = offset & ~(BITS_PER_LONG - 1); + unsigned long result = size; unsigned long tmp; if (offset >= size) return size; - size -= result; + size -= (offset & ~(BITS_PER_LONG - 1)); offset %= BITS_PER_LONG; - if (!offset) - goto aligned; - - tmp = __reverse_ulong((unsigned char *)p); - tmp |= ~((~0UL << offset) >> offset); - - if (size < BITS_PER_LONG) - goto found_first; - if (tmp != ~0UL) - goto found_middle; - - size -= BITS_PER_LONG; - result += BITS_PER_LONG; - p++; -aligned: - while (size & ~(BITS_PER_LONG - 1)) { + + while (1) { + if (*p == ~0UL) + goto pass; + tmp = __reverse_ulong((unsigned char *)p); + + if (offset) + tmp |= ~0UL << (BITS_PER_LONG - offset); + if (size < BITS_PER_LONG) + tmp |= ~0UL >> size; if (tmp != ~0UL) - goto found_middle; - result += BITS_PER_LONG; + goto found; +pass: + if (size <= BITS_PER_LONG) + break; size -= BITS_PER_LONG; + offset = 0; p++; } - if (!size) - return result; - - tmp = __reverse_ulong((unsigned char *)p); -found_first: - tmp |= ~(~0UL << (BITS_PER_LONG - size)); - if (tmp == ~0UL) /* Are any bits zero? */ - return result + size; /* Nope. */ -found_middle: - return result + __reverse_ffz(tmp); + return result; +found: + return result - size + __reverse_ffz(tmp); } void register_inmem_page(struct inode *inode, struct page *page) -- 2.4.9 (Apple Git-60) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
